ZWO ASI choices, 174 or 178 advice please

[Owmuchonomy]

So I need the forum's advice to top up my research. For a Lunt 60 Ha1200 imaging set up AND a SCT 9.25" lunar imaging set up which would you go for and why? The ASI 174 mono or the ASI 178mono.? If it makes a difference I am stuck with USB 2.0 for a few months until I can upgrade. I think I know the answer but I just want to get you more experienced imagers views please.

[knobby]

Do you mean the ASI 178 mono ?

[michael.h.f.wilkinson]

I have the ASI174MM and it is superb (but you only get the most out of it on USB 3.0). It will readily capture a full disk in the LS60, and it performs well for lunar work in my C8, so the C9.25 would work well. The ASI178 has a chip of 7.4x5mm. Getting the whole solar disk on it would be a bit of a squeeze, I guess. You would get more resolution, and the pixel size is close to optimal for an F/10 SCT (no Barlow needed). Having said that, I would guess the camera will be VERY slow in terms of frame rate on a USB 2.0 laptop.

[Owmuchonomy]

10 minutes ago, knobby said:

Do you mean the ASI 178 mono ?

Yep.

[Owmuchonomy]

3 minutes ago, michael.h.f.wilkinson said:

I have the ASI174MM and it is superb (but you only get the most out of it on USB 3.0). It will readily capture a full disk in the LS60, and it performs well for lunar work in my C8, so the C9.25 would work well. The ASI178 has a chip of 7.4x5mm. Getting the whole solar disk on it would be a bit of a squeeze, I guess. You would get more resolution, and the pixel size is close to optimal for an F/10 SCT (no Barlow needed). Having said that, I would guess the camera will be VERY slow in terms of frame rate on a USB 2.0 laptop.

Yes full chip just for full disk could easily be less than 30fps.

[michael.h.f.wilkinson]

As the frame rate will be bus-limited, the 6.4 Mpixel camera will run at roughly 1/3rd of the frame-rate of the 2.3Mpixel one. Assuming the ASI174 can chug along at around 10 FPS at  full frame under USB 2.0, the ASI178 would be crawling at 3FPS or so

[michael.h.f.wilkinson]

I am considering adding an ASI178 to the arsenal, for lunar and perhaps WL solar in the C8 without using PowerMates or TeleXtenders

[Owmuchonomy]

2 minutes ago, michael.h.f.wilkinson said:

I am considering adding an ASI178 to the arsenal, for lunar and perhaps WL solar in the C8 without using PowerMates or TeleXtenders

Yes, that is an option but funds are limited for me at the moment. I think I need to get to USB 3 next.

[michael.h.f.wilkinson]

I wonder if the ASI178 supports binning. I cannot currently find that. If so, you could use the ASI178MM at 1.6Mpixel on USB2.0 at reasonable frame rates

[Owmuchonomy]

well there is this thread I read but they are discussing DSOs.

http://zwoug.org/viewtopic.php?f=21&t=2275&hilit=178+binning

[IanL]

I got a Lunt LS60/B1200 and ASI174mm a couple of weeks ago. I am currently limited to USB2 until I can upgrade.  The setup is great for solar (haven't tried lunar or planetary with any of my other scopes yet).

At native F/L you can easily do a full disk and actually set a smaller ROI which ups the frame rate somewhat. I am getting about 18FPS which is OK until I get a new USB3 setup. The image is under sampled but using drizzling in Autostakkert you can recover some of that readily.

The big advantage of the 174 is the global shutter vs the rolling shutter on the 178, important to capture clean frames in the short moments of good seeing. Also the larger pixels give more well depth and thus dynamic range.  This is useful for solar in particular, as I find I can do one set of exposures for both disk and prominences rather than having to do two different exposures.

You might also want to look in to Newton's rings issues if you plan to use a Barlow or Powermate. I haven't seen any with my fairly basic Meade 2x Barlow, but plenty of reports of them with some setups using ASI cameras. Flats or a tilting adaptor can remove them though.

[Owmuchonomy]

Thanks Ian great advice. Solar and Newtons rings is a big ZWO users topic for the ASI 120 but not so much I can see for the other variants.

[michael.h.f.wilkinson]

I do get some slight Newton rings in the ASI174MM, but can usually control them with flats. Not sure about the ASI178MM. The rolling shutter of the 178 chip doesn't seem to affect Luc's results here, BTW:

 

[Owmuchonomy]

On 14 April 2016 at 22:21, IanL said:

I got a Lunt LS60/B1200 and ASI174mm a couple of weeks ago. I am currently limited to USB2 until I can upgrade.  The setup is great for solar (haven't tried lunar or planetary with any of my other scopes yet).

At native F/L you can easily do a full disk and actually set a smaller ROI which ups the frame rate somewhat. I am getting about 18FPS which is OK until I get a new USB3 setup. The image is under sampled but using drizzling in Autostakkert you can recover some of that readily.

The big advantage of the 174 is the global shutter vs the rolling shutter on the 178, important to capture clean frames in the short moments of good seeing. Also the larger pixels give more well depth and thus dynamic range.  This is useful for solar in particular, as I find I can do one set of exposures for both disk and prominences rather than having to do two different exposures.

You might also want to look in to Newton's rings issues if you plan to use a Barlow or Powermate. I haven't seen any with my fairly basic Meade 2x Barlow, but plenty of reports of them with some setups using ASI cameras. Flats or a tilting adaptor can remove them though.

Hi Ian.  Have you given the PC upgrade any thought? I know nothing about PCs (I am all MAC save for my old Dell USB2).  I was wondering if you could point me at a suitable USB 3.0 machine specification for my ASI 174 MM?  The ZWO users group are adamant that a SSD is required of speeds >350M/S whatever that means?

[IanL]

2 hours ago, Owmuchonomy said:

Hi Ian.  Have you given the PC upgrade any thought? I know nothing about PCs (I am all MAC save for my old Dell USB2).  I was wondering if you could point me at a suitable USB 3.0 machine specification for my ASI 174 MM?  The ZWO users group are adamant that a SSD is required of speeds >350M/S whatever that means?

I haven't given it serious thought yet unfortunately.  I'd say you are looking for:

- Intel Core i5 processor at a minimum (i7 would be better but only if the price is right).

- 8GB of RAM, 16GB would be better.

- Check the number of USB3 ports - cheaper models might only have one USB3 and the rest USB2.

- 256GB SSD - 512GB would be better.  You might look at models with a 128GB SSD and a larger standard hard disk, but then you're going to have to be spending time during capture sessions copying files from one to the other.

- Screen, keyboard, etc. aren't so important if you are just using it for capture, but more important if you are using it for processing or as a general-purpose machine.

The cost is going to be around £1,000 for somewhere in the bottom-middle of the range of options above. You may get it a bit under or over depending on how you shop around and what you want.  Obviously buy from somewhere reputable and a decent brand as you may need to call on the warranty at some point!

Personally I won't be going down that route though, but I build my own PCs from scratch so this isn't for everyone.  I plan to build a micro-ATX machine - very small format PCs.  I reckon I can beat the above specification for under £500, but bear in mind:

- I only have to lug this from the house to the garden and back, so being self-contained or battery powered is not a concern for me.  Going to build the machine, screen, etc. in to a tool chest for convenience so it's going to be way better than my current laptop.

- I can do my own tech support and repair/replace parts as I need, install operating systems and generally figure stuff out for myself.

- I have some things like spare screens and keyboards knocking about the house which helps with cost.  We're a family of four and we're outnumbered 1.5 to 1 by working PCs and laptops, and that's before you get to the dead laptops and PCs, android tablets, phones, games consoles, raspberry Pis and the like.  You get the picture.

[Owmuchonomy]

It must be so satisfying to be able to put that together yourself. Thank you for the advice

[riklaunim]

I have ASI178MM. I picked this one over ASI174 to get better sensor in terms of pure performance. Depending on telescopes you would want to use 2.4 pixels may be to small - for f/ratios slower than around f/13-14.

[Owmuchonomy]

17 hours ago, riklaunim said:

I have ASI178MM. I picked this one over ASI174 to get better sensor in terms of pure performance. Depending on telescopes you would want to use 2.4 pixels may be to small - for f/ratios slower than around f/13-14.

Yes, I think I may buy 2 cameras for this reason.

[Owmuchonomy]

20 hours ago, IanL said:

I haven't given it serious thought yet unfortunately.  I'd say you are looking for:

- Intel Core i5 processor at a minimum (i7 would be better but only if the price is right).

- 8GB of RAM, 16GB would be better.

- Check the number of USB3 ports - cheaper models might only have one USB3 and the rest USB2.

- 256GB SSD - 512GB would be better.  You might look at models with a 128GB SSD and a larger standard hard disk, but then you're going to have to be spending time during capture sessions copying files from one to the other.

- Screen, keyboard, etc. aren't so important if you are just using it for capture, but more important if you are using it for processing or as a general-purpose machine.

The cost is going to be around £1,000 for somewhere in the bottom-middle of the range of options above. You may get it a bit under or over depending on how you shop around and what you want.  Obviously buy from somewhere reputable and a decent brand as you may need to call on the warranty at some point!

Personally I won't be going down that route though, but I build my own PCs from scratch so this isn't for everyone.  I plan to build a micro-ATX machine - very small format PCs.  I reckon I can beat the above specification for under £500, but bear in mind:

- I only have to lug this from the house to the garden and back, so being self-contained or battery powered is not a concern for me.  Going to build the machine, screen, etc. in to a tool chest for convenience so it's going to be way better than my current laptop.

- I can do my own tech support and repair/replace parts as I need, install operating systems and generally figure stuff out for myself.

- I have some things like spare screens and keyboards knocking about the house which helps with cost.  We're a family of four and we're outnumbered 1.5 to 1 by working PCs and laptops, and that's before you get to the dead laptops and PCs, android tablets, phones, games consoles, raspberry Pis and the like.  You get the picture.

Hi Ian, FYI I am going to try my ASI 174 MM with my Macbook Air first (SSD).  OA Capture 0.9 should have ironed out the OSX issues.  If it works as well as my Dell I will make the assumption I can upgrade the Macbook.  This would be so much better for me if its the case. On the desk in my office it works fine.

[michael.h.f.wilkinson]

My ASI174MM performs fine on a Core-M based laptop. The key is I/O speed, not compute performance. That does matter when stacking, but there is less of a hurry when you do that. My ASUS Zenbook UX305 has a 128 GB SSD, which is fast enough, but too small for really big capture sessions. I got a Samsung T1 500GB external USB 3.0 SSD. This can max out the USB 3.0  bus at 450 MB/s. Because the laptop only has USB 3.0 ports (3 of them) I can simply route all the data from camera straight onto the external SSD, and maintain 128 FPS at full resolution.

I wouldn't be surprised if a similar machine with a Core-i3 would actually perform equally well during capture (might try that with the kids' machines).

 

[riklaunim]

38 minutes ago, Owmuchonomy said:

Yes, I think I may buy 2 cameras for this reason.

I would say you may try to optimize it to one camera. Depending on telescopes/usages it should be doable. If needed also Point Grey has a set of cameras with for example 3,75 pixels.